Best grown in humusy, medium moisture, well-drained soils in full sun. Best flowering and disease resistance occur in full sun. Good soil drainage is essential to combat potential soft rot problems. Avoid use of mulch for the same reason. Heavy clay soils such as those present in much of the St. Louis area must be amended prior to planting (e.g., add gypsum, coarse sand, organic matter) or raised plantings should be considered. Plant rhizomes shallowly (cover with 1/2" soil) and 12-24" apart in mid to late summer (July to early September). Fertilize lightly in early spring. Fertilize again after bloom and continue to provide uniform moisture throughout the summer to encourage the late summer to fall rebloom. Avoid overhead watering. Deadhead individual spent flowers and remove flowering stems to the ground after bloom. Divide plants when overcrowding occurs (every 3-4 years).
'Spirit of Memphis' is a reblooming (or remontant) tall bearded iris which typically grows to 35" tall and slowly spreads by rhizomes. Standards and falls are bright yellow with brown haft markings and heavily ruffled. Reblooming iris are noted for producing both a main bloom in spring and an additional bloom from late summer into fall (often to frost). The time and duration of the rebloom may vary considerably by climatic region, however. Sword-shaped, linear leaves. Zurbrigg 1977.
The major insect pest of bearded iris is iris borer. Major disease problems are bacterial soft rot and fungal leaf spot. Good sanitation practices are the most important component of any disease/insect control program: promptly remove and destroy diseased foliage/rhizomes, promptly remove and destroy borer-infected foliage/rhizomes and perform an annual clean-up of all debris and foliage from beds in fall after frost. The most frequent causes of failure to flower or sparse flowering are (1) rhizomes are planted too deep, (2) plants are located in too much shade, (3) plants were given too much fertilizer or (4) plants have become overcrowded and need division.